Process for the Preparation of an Edible Dispersion Comprising Oil and Structuring Agent

ABSTRACT

The invention relates to a process for the preparation of an edible dispersion comprising oil and structuring agent and one or more of an aqueous phase and/or a solid phase, in which the dispersion is formed by mixing oil, solid structuring agent particles and the aqueous phase and/or the solid phase, wherein the solid structuring agent particles have a microporous structure of submicron size particles.

FIELD OF THE INVENTION

The present invention relates to a process for the preparation of anedible dispersion comprising oil and structuring agent, in particular tosuch dispersions comprising oil and structuring agent as continuousphase and a dispersed phase. The dispersed phase may be an aqueousliquid (thus forming a water-in-oil emulsion) or a solid particulatematter (thus forming a suspension). The invention further relates to theuse of micronised fat powder to stabilise oil-containing dispersions.

BACKGROUND OF THE INVENTION

Edible dispersions comprising oil and structuring agent are well known.Examples of well-known products that substantially consist of suchedible dispersions are water-in-oil emulsions, such as for instancemargarines and spreads. These edible dispersions typically have an oilphase that is a blend of liquid oil and fat that is solid at normalambient temperature (20° C.). This solid fat, often also designated ashardstock, acts as structuring agent, and its function is to stabilisethe dispersion. For a margarine or spread, ideally the structuring agenthas such properties that it should have melted or dissolved at mouthtemperature, otherwise the product has a heavy, waxy mouthfeel.

Other known dispersions comprising oil and structuring agent aredisclosed in EP-A-775444 and WO 98/47386. Herein the dispersed phase isa dry particulate matter, such as e.g. flour, starch, salt, spices,herbs etc.

Generally, the edible dispersions comprising structuring agent areprepared according to prior art processes that encompass the followingsteps:

-   1) dispersion of the aqueous phase and/or the solid phase through    the oil phase, at a temperature where the oil phase, including the    structuring agent is liquid;-   2) formation of a fat crystal network to stabilise the resulting    dispersion and give the product some degree of firmness;-   3) modification of the crystal network to produce the desired    firmness and confer plasticity.

These steps are usually conducted in a process that involves apparatusthat allow heating, cooling and mechanical working of the ingredients,such as the churn process or the votator process. The churn process andthe votator process are described in Ullmanns Encyclopedia, FifthEdition, Volume A 16 pages 156-158. Using these techniques excellentdispersions (spreads) having high emulsion stability and good meltingproperties in the mouth can be prepared.

However, a disadvantage of the known processes is that the processinvolves a heating step and a cooling step and therefore requires a lotof energy. In a dispersion with for instance 4 wt. % structuring agentthe whole weight of the dispersion (100 wt. %) needs to be heated andcooled. Another disadvantage of the known processes is that the choiceof fats that can practically be used as structuring agent is ratherlimited. If the melting point of the structuring agent is too high themelting properties in the mouth are unsatisfactory. If on the otherhand, the melting point is too low, the emulsion stability will benegatively affected. Moreover the amount of saturated fatty acids in thestructuring agent is usually relatively high. Saturated fatty acids area known risk factor for cardiovascular health.

Further disadvantage of the known processes is that the product maydeteriorate due to the changes in temperature caused by the heating andcooling step and that heat-sensitive ingredients cannot be incorporated.

Powdered fat is well known in the prior art. It may be preparedaccording to various processes, known in the art. Micronised fat is alsoknown in the prior art. EP-B-744992 describes the preparation ofmicronised fat particles by dissolution of gas (carbondioxide) in thefat under pressure and decompressing the mixture in such way that thetemperature falls below the solidification point of the fat, so thatmicronised particles are formed.

EP-A-1238589 describes a method for forming a food product, whichcontains an emulsion in which the food product in liquid form iscontacted with a cryogen so as to cool the liquid product and effect arapid conversion of the liquid to a solid. A disadvantage of this knownprocess is that still the whole emulsion has to be heated above themelting point of the structuring agent.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a process thatrequires less energy for the preparation of a dispersion comprising thestructuring agent. Another object is to provide such a process thatallows the use of more types of structuring agent, especially more sortsof hardstock. A further object of the invention is a reduction of theamount of saturated fatty acids in the hardstock. Still a further objectof the invention is to provide a process for the preparation of adispersion that allows the incorporation of heat-sensitive ingredientsand/or that avoids deterioration of the emulsion.

One or more of these objects is attained according to the invention thatprovides a process for the preparation of an edible dispersioncomprising oil and structuring agent and one or more of an aqueous phaseand/or a solid phase, in which the dispersion is formed by mixing oil,solid structuring agent particles and the aqueous phase and/or the solidphase, wherein the solid structuring agent particles have a microporousstructure of submicron size particles. Preferably, the solid structuringagent particles are at least 50% alpha-polymorph.

According to the invention the heating and cooling step of the emulsioningredients that is needed in the prior art processes may be omitted orreduced and a stable dispersion can be made.

Preferably, the solid structuring agent particles are at 50% or morealpha-polymorph, more preferably 70% or more alpha-polymorph and mostpreferably 90% or more alpha-polymorph.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a process for the preparation of a dispersion.A dispersion is herein defined as a system in which two or more phasesthat are insoluble or only slightly soluble are distributed in oneanother.

The dispersion may be an emulsion, a suspension or foam or anycombination thereof, it may be oil continuous, water continuous orbi-continuous. Preferably the dispersion is oil continuous, morepreferably an oil continuous emulsion or oil continuous suspension.

Where a solid phase is present in the dispersion according to theinvention, it is preferably a solid phase of dry particulate matter.

Where an aqueous phase is present in the dispersion according to theinvention, it is preferably a dispersed aqueous phase.

According to the invention, the dispersion is formed by mixing oil, thesolid structuring agent particles and the other phase or phases of thedispersion, such as for example an aqueous phase, a solid phase and/or agas phase. The mixing of the ingredients may be done in any order, i.e.the ingredients/phases may all be mixed in one mixing step oralternatively the mixing may be executed in more than one step. Forinstance an oil phase with the structuring agent particles may be mixedand a water phase may be prepared separately and later mixed with theoil phase.

According to the invention, the solid structuring agent particles shouldhave a microporous structure of submicron size particles. An example ofa microporous structure according to the invention is shown in FIGS. 6and 7 hereafter. The submicron particles typically have the shape asshown in FIG. 7, and consist of platelets with submicron dimensions. Thethickness of the platelets should be submicron, preferably the thicknessis on average 0.01-0.5 μm, more preferably 0.03-0.2 μm, even morepreferably 0.06-0.12 μm.

Equivalent good results were obtained for a microporous structure ofmore bubble-like shape, such as shown in FIG. 10, hereafter. In suchmicroporous structure the wall thickness of the bubbles should besubmicron, for instance on average 0.01-0.5 μm, more preferably 0.03-0.2μm, even more preferably 0.06-0.12 μm.

The microporous structure, may, in the course of the preparation of thedispersion, for instance through the force of a mixer, be broken intosubmicron particles. The resulting submicron particles will form thestructuring network of the dispersion.

Preferably, the structuring agent is edible fat. Edible fats consistpredominantly of triglycerides. Typically such edible fats suitable asstructuring agent are mixtures of triglycerides, some of which have amelting point higher than room or ambient temperature and thereforecontain solids in the form of crystals.

The solid fat structuring agent, also denoted as hardstock or hardstockfat, serves to structure the fat phase and helps to stabilise thedispersion.

For imparting to common margarine a semi-solid, plastic, spreadableconsistency this stabilising and structuring functionality plays animportant role. The crystals of the solid fat form a network throughoutthe liquid oil resulting into a structured fat phase. The aqueous phasedroplets are fixed within the spaces of the lattice of solid fatcrystals. In this way coalescence of the droplets and separation of theheavier aqueous phase from the fat phase is prevented.

Generally, fats with a high content of HUH triglycerides show goodstructuring properties. H denotes a C16-C24 saturated fatty acidresidue, such as palmitic acid (C16) or stearic acid (C18) and U denotesan unsaturated C18 fatty acid residue, such as oleic acid (C18:1) orlinoleic acid (C18:2). Examples of suitable edible fat structuringagents (hardstock fats) are palm oil partially hydrogenated to a meltingpoint of 44° C. or an interesterified mixture of palm oil and a lauricfat.

Further common ingredients of the fat phase are emulsifiers, such asmonoglycerides and lecithin, colouring agents and flavours.

The structuring agent should be added to the dispersion in the form ofsolid structuring agent particles. Preferably the solid structuringagent particles should have an alpha-polymorph.

The following nomenclature of the polymorphic forms of the structuringagent is used herein:

1. α-polymorph (alpha polymorph): a form that gives only oneshort-spacing line in the X-ray diffraction pattern near 4.15 Å.2. β′-polymorph (beta-prime polymorph): a form that gives two shortspacing lines near 3.80 Å and 4.20 Å in the X-ray diffraction patternand also shows a doublet in the 720 cm⁻¹ in the infrared absorptionspectrum3. β-polymorph (beta polymorph): a form that does not satisfycriteria 1. or 2.

See for an explanation of polymorphism and the above definition:Gunstone, F. D.; Harwood, J. L.; Padley, F. B.; The Lipid Handbook,second edition, Chapman and Hall, page 405.

The solid structuring agent particles preferably have an averageparticle size (D_(3,2)) of 60 micrometer or less, more preferably thesolid structuring agent particles have an average particle size of 30micrometer or less. The average particle size (D_(3,2)) is determined asindicated in the examples.

Preferably the solid structuring agent particles are prepared using amicronisation process. In the micronisation process the solidstructuring agent particles are prepared by preparing a homogeneousmixture of structuring agent and liquified gas or supercritical gas at apressure of 5-40 MPa and expanding the mixture through an orifice, undersuch conditions that a spray jet is applied in which the structuringagent is solidified and micronised. The liquified gas or supercriticalgas may be any gas that may be used in the preparation of food products,for example carbondioxide, propane, ethane, xenon or other noble gases.Carbondioxide and propane are preferred. Carbondioxide is mostpreferred. Advantages of carbondioxide are that it has a mild (31° C.)critical temperature, it is non-flammable, nontoxic, environmentallyfriendly and it may be obtained from existing industrial processeswithout further contribution to the greenhouse effect. It is fairlymiscible with oil and is readily recovered owing to its high volatilityat ambient conditions. Finally liquid CO₂ is the second least expensivesolvent after water.

The temperature of the mixture of structuring agent and liquified gas orsupercritical gas is preferably such that the mixture forms ahomogeneous mixture. Advantageously, the temperature of the mixture ofstructuring agent and liquified gas or supercritical gas is below theslip melting point of the structuring agent at atmospheric pressure andabove the temperature at which phase separation of the mixture occurs.Under such conditions the smallest micronised particles may be obtained.

The pressure and temperature of the mixture of structuring agent andliquified or supercritical gas is preferably such that a large amount ofthe gas may be dissolved in the structuring agent. The amount dissolvedwill be determined by the phase diagram of the mixture of structuringagent and liquified or supercritical gas. At higher pressures as well asat lower temperatures more gas will dissolve in the structuring agent.

Preferably the temperature and pressure are chosen such that 10 wt. % ormore, more preferably 20 wt. % or more or most preferably 30 wt. % ormore of gas is dissolved in the liquid phase. The mixture of structuringagent and liquefied or supercritical gas may contain additionalsubstances, such as for instance oil. We have found that the addition ofoil may reduce sintering of the micronised particles of the structuringagent.

The mixture-containing structuring agent and liquefied or supercriticalgas is depressurised over a small orifice or nozzle, to break up themixture into small droplets. The break-up of the mixture into dropletscan be assisted e.g. by internals inside the nozzle before the orificeto generate a whirl, or by passing a gas at a high flow rate near theorifice.

The mixture is depressurised into a volume where the pressure is higherthan, equal to or lower than atmospheric pressure.

We have found that sintering, agglomeration and ripening of micronisedparticles of the structuring agent will lead to a reduced performance ofthe particles for structuring the dispersion.

To avoid sintering, agglomeration and/or ripening of the micronisedparticles, preferably a gas jet is applied in addition to the flow ofthe spray jet. The additional gas jet is most effective when the gas jetis positioned such that recirculation of material expanded through theorifice is reduced or avoided. Especially advantageous is a positionwherein the gas from the gas jet flows essentially tangentially to theflow direction of the spray jet. Most advantageously the gas inlet forthe gas jet is positioned behind the exit of the nozzle, see FIG. 2.FIG. 2 shows that the additional gas inlet (1) behind the exit of thenozzle (2) creates a gas flow (3) tangentially to the flow of the sprayjet (4).

To further avoid agglomeration and ripening, the spray jet is preferablysprayed into a collection chamber, and a flow of gas having atemperature lower than the slip melting point of the structuring agentis fed into the collection chamber.

Preferably the edible dispersion according to the invention is a waterand oil containing emulsion, optionally including a solid phase. Theemulsions are preferably oil continuous. Examples of suitable emulsionsare table spreads, dressings, soups, sauces, shortenings, cooking oils,frying oils, whipping creams and mayonnaises.

A stable dispersion is herein defined as dispersion that shows an oilexudation of less than 5% after storage for 15 weeks at 15° C., measuredaccording to the method described in the examples.

A further preferred edible dispersion according to the invention is adispersion of a solid matter, preferably a dry particulate matter,dispersed in a continuous phase of oil and structuring agent. Preferredmaterial for the dry particulate matter is one or more of flour, starch,salt, herbs (e.g. dried herbs), spices and mixtures thereof. Preferablyin such dispersions, the amount of solid matter is 30-75 wt. %, morepreferably 40-65 wt. % based on total weight of the dispersion.

The amount of structuring agent should be such that a suitably stabledispersion is obtained. When the structuring agent is micronised fat,the amount is preferably 1-20 wt. %, more preferably 4-12 wt. % based ontotal weight of the dispersion.

DESCRIPTION OF THE FIGURES

FIG. 1: Schematic view of the micronisation apparatus used in theexamples

FIG. 2: Schematic view of the nozzle configuration with gas inlet fortangential gas-flow.

FIG. 3: SEM Photograph of micronised fat powder prepared in example 1(magnification 250×)

FIG. 4: SEM Photograph of micronised fat powder prepared in comparativeexperiment A (magnification 250×)

FIG. 5: SEM Photograph of micronised fat powder prepared in comparativeexperiment B (magnification 250×)

FIG. 6: SEM Photograph of micronised fat powder prepared in example 1(magnification 1000×)

FIG. 7: Enlarged SEM photograph of the micronised fat powder of example1

FIG. 8: Enlarged SEM photograph of the micronised fat powder of example8

FIG. 9: Enlarged SEM photograph of the micronised fat powder of example9

FIG. 10 Enlarged SEM photograph of the micronised fat powder of example10

EXAMPLES General Method to Determine Slip Melting Point

The slip melting point of structuring agent is determined in accordancewith F. Gunstone et al, The Lipid Handbook, second edition, Chapman andHall, 1995, page 321, Point 6.2.3, Slip point.

Method to Determine D_(3,2) of the Particle Size Distribution ofMicronised Fat Particles

Low-angle laser light scattering (LALLS, Helos Sympatic) was used tomeasure the average particle size (D_(3,2)). The fat particles weresuspended in water in a quixel flow cuvette with an obscuration factorof 10-20%. The diffraction pattern was measured at 632.8 nm with a lensfocus of 100 mm and a measurement range of 0.5-175 μm. Calculations werebases on the Fraunhofer theory.

A full description of the principle of LALLS is given in ISO 13320-1.

Method to Determine D_(3,3) of Water Droplet Size Distribution in anEmulsion

The water droplet size was measured using a well-known low resolutionNMR measurement method. Reference is made to Van den Enden, J. C.,Waddington, D., Van Aalst, H., Van Kralingen, C. G., and Packer, K. J.,Journal of Colloid and Interface Science 140 (1990) p. 105.

Method to Determine Oil Exudation

Oil exudation is determined by measuring the height of the free oillayer that appears on top of the product. This free oil layer isconsidered a product defect. In order to measure oil exudation, theproduct is filled into a scaled glass cylinder of 50 ml. The fillingheight is 185 mm. The filled cylinder is stored in a cabinet at constanttemperature (15° C.). Height measurements are executed every week, bymeasuring the height of the exuded oil layer in mm with a ruler. Oilexudation is expressed as the height of the exuded oil layer divided bythe original filling height and expressed in %. Shaking of the cylindersshould be avoided.

Method to Determine Pourability

Pourability for pourable compositions according to the invention ismeasured according to the standard Bostwick protocol. The Bostwickequipment consists of a 125 ml reservoir provided with a outlet near thebottom of a horizontally placed rectangular tub and closed with avertical barrier. The tub's bottom is provided with a 25 cm measuringscale, extending from the outlet of the reservoir. When equipment andsample both have a temperature of 15° C., the reservoir is filledhalfway with 62.5 ml of the sample after it has been shaken by hand tentimes up and down. When the closure of the reservoir is removed thesample flows from the reservoir and spreads over the tub bottom. Thepath length of the flow is measured after 15 seconds. The value,expressed as cm per 15 seconds is the Bostwick rating, which is used asyardstick for pourability.

Example 1 Fat Micronisation

A set-up was constructed to dissolve carbon dioxide in the melt andexpand the mixture over a nozzle to atmospheric pressure. The micronisedproduct was collected in a drum (6) of 250 liters. The set-up isillustrated in FIG. 1.

-   Autoclave The equipment consists of a 1-liter autoclave (2) equipped    with a mechanical stirrer (6-blade turbine impeller), a water jacket    for heating and a Pt-100 resistance thermometer. The inner diameter    of the autoclave is 76 mm. The autoclave has connections at the top    and at the bottom.-   Tubing The bottom connection of the vessel was used to pressurise    the system with carbon dioxide or to lead the mixture to the nozzle.    A 3-way valve (12) is used to switch between CO₂ supply (1) and    nozzle (3). To expel the mixture from the vessel the CO₂ is supplied    to the top of the autoclave via valve (11). The length of tube    between the bottom connection and the nozzle (3) is approximately    30 cm. All tubing has an outer diameter of ¼″ (inner diameter    approximately ⅛″) and is equipped with electrical tracing.    Additional gas, N2 or He, can be supplied through (10) to maintain a    constant pressure inside the autoclave during the expansion over the    nozzle-   Nozzle The nozzle (3) can be designed with different orifice    diameters (opening outlet) and cores (construction of the supply to    the orifice). For this work nozzles were used with an orifice of    0.34 mm and standard core. The nozzle was heated by electrical    tracing and its temperature was registered by a thermocouple Pt-100.-   Collection The nozzle was mounted to a Perspex tube (7) of 30 cm    diameter and 20 cm length to allow observation of the jet during    expansion. This transparent Perspex tube (7) with the nozzle (3) was    mounted on top of an oil-drum (6) (250 liters) with a removable lid,    which served as the collection chamber. The lid of the drum has an    outlet (8) to allow the expanded. CO₂ to escape. A separator (9)    retains the solid particles in the collection chamber. An additional    gas jet (CO₂) may be supplied though nozzle (4) connected to a gas    supply (CO₂ bottle) (5).-   Loading The equipment was heated to the required temperature.    Approximately 300 grams of fat (RP70, rapeseed oil hardened to a    slip melting point of 70° C.) was completely melted and heated to 20    degrees above its melting point and charged into the autoclave.-   Equilibrium The autoclave was pressurised in about 10 minutes    through the bottom connection. During pressurisation the CO₂ supply    to the top was closed. After reaching the final pressure the top    valve was opened and the 3-way valve was closed. The melt was    allowed to absorb CO₂ and equilibrate for 30 minutes, while stirring    the mixture and supplying additional CO₂. The equilibrium pressure    in the autoclave was 15 MPa and the temperature in the autoclave was    60° C.-   Expansion To expand the melt the stirrer was stopped and the supply    of additional gas to the collection chamber was turned on. Next the    α-way valve was switched to supply the mixture to the nozzle. During    expansion of the mixture in example 1 the pressure in the autoclave    was maintained by the CO₂ supply. In examples 2 and 3 the pressure    in the autoclave was increased to and maintained at 15 MPa by    supplying He to the top of the vessel, after first equilibrating    with CO₂.    -   A micronised fat powder that was obtained which was a very fine        and dry solid powder. The powder was 100% alpha-polymorph. In        the X-ray diffractogramme, peaks for the β′ and β-polymorph were        totally absent. The micronised fat powder was stored at 5° C.        When stored at 5° C. the micronised fat powder stayed 100%        alpha-polymorph during more than one month.

The micronisation parameters are given in table 2.

Preparation of an Edible Water-in-Oil Emulsion

A pourable margarine was prepared with the composition shown in table 1:

TABLE 1 Composition of pourable margarine Amount Ingredient (wt. %) Oilphase Sunflower oil 79.62 Micronised Rp 70 powder 1.95 Lecithin BolecMT¹ 0.18 Fractionated lecithin 0.10 Cetinol² Beta-carotene (0.4 wt. %0.15 solution in sunflower oil) Water phase Water 16.5 Sodium chloride1.5

Explanation of Table 1:

The balance of all composition to 100% is water RP 70: Rapeseed oilhardened to a slip melting point of 70° C.

1: Lecithin was hydrolysed soybean lecithin (Bolec Mont.) obtained fromUMZ (Unimills Zwijndrecht, Netherlands)2: Alcohol-soluble fraction from fractionation of native soybeanlecithin with alcohol; Cetinol from UMZ.

The water phase was prepared by adding salt to distilled water andadjusting the pH of distilled water from 7.7 to 4.0 using 5 wt. % citricacid, and heated for 5 minutes in a bath of 60° C. to dissolve thesolids. The oil phase was prepared by dissolving the emulsifieringredients and β-carotene in the total amount of sunflower oil at 15°C. Subsequently the micronised fat powder was added to the oil phasecarefully using a spatula and the oil phase was mixed with a Turrax at22000 rotations per minute (rpm) for 6 minutes. Then the water phase wasadded to the oil phase and the resulting mixture was mixed with a Turraxfor 5 minutes at 23500 rpm in a water bath at having a temperature of15° C.

The temperature of the mixture in the Turrax increased due to theviscous dissipation. However during the whole experiment the temperaturewas kept below 20° C. The Turrax (type T50) was delivered by Janke &Kunkel IKA Labortechnik. This type of Turrax is designed to minimise airentrainment.

The emulsion was partly poured into a glass cylinder and partly into atwist off pot of 100 ml and both were containers were stored in acabinet at 15° C.

Results

The prepared emulsions were tested in accordance with the test methodsdescribed herein and the results of the tests are given in table 3. ASEM photograph of the micronised fat powder of example 1 (magnification250 times) is given in FIG. 3, with magnification of 1000 times in FIG.6, and with magnification of 2000 times in FIG. 7.

Comparative Experiment A

Comparative experiment A was conducted as example 1, however the fatmicronisation step was modified in that the equilibrium pressure in theautoclave was 5 MPa instead of 15 MPa. Before and duringdepressurisation over the nozzle the mixture in the autoclave waspressurised with Helium to 15 MPa.

The results are shown in table 3. A SEM-photograph of the micronised fatpowder is given in FIG. 4.

Comparative Experiment B

Comparative experiment B was conducted as example 1, however the fatmicronisation step was modified in that the equilibrium pressure in theautoclave was 10 MPa instead of 15 MPa. Before and duringdepressurisation over the nozzle the mixture in the autoclave waspressurised with Helium to 15 MPa.

The results are shown in table 2. A SEM-photograph of the micronised fatpowder is given in FIG. 5.

All powders of example 1 and comparative experiments A and B showed thepresence of 100% alpha-polymorph material. The micronised powderaccording to example 1 has a low particle size (see table 2) and has amicroporous structure of submicron size particles, as is shown in FIG.6. In contrast the powders of comparative experiments A and B have ahigher particle size and a structure in which submicron size particlesare not apparent.

TABLE 2 Micronisation parameters of example 1 and comparativeexperiments A and B Amount of Equilibrium CO₂ Pressure Temperaturedissolved D_(3,2) Example (MPa) (° C.) (wt. %) (μm) 1 150 60 19 39 A 5070 7 72 B 100 60 16 75

TABLE 3 Oil exudation (%) of the emulsions of example 1 and comparativeexperiments A and B as function of the storage time at 15° C. StorageComp. Ex. Comp. Ex. time Example 1 A B 1 day 35.1 2 days 40.5 3 days 048.6 1 week 0 1.1 59.5 2 weeks 0 16.2 59.5 3 weeks 18.9 62.2 4 weeks62.2 5 weeks 6 weeks 7 weeks 0.5 18.9 8 weeks 9 weeks 64.9 10 weeks 11weeks 0.5 18.9 12 weeks 14 weeks 64.9 15 weeks 0.5 16 weeks 21.6

The results show that the emulsion according to example 1 shows a verylow oil exudation, which whereas those of comparative experiments A andB have a high oil exudation and therefore the emulsions are not stable.

Examples 2-4

Example 1 was repeated, but now instead of fat a mixture of fat andsunflower oil was micronised. The composition of the mixture of fat andoil is shown in table 3. In the preparation of the emulsion a Turraxspeed of 8000 rpm was used and the Turrax time was 4 minutes.

TABLE 4 Micronisation parameters and emulsion properties of examples 2-4Fraction Texture of sunflower micronised Bostwick D_((3,3)) Example oil(wt. %) product (cm) (μm) 2 22 Fine dry 14 4.36 powder 3 50 Slightly14.6 3.06 granular somewhat sticky powder 4 75 Ointment 10 — likestructure

All micronised products of examples 2-4 showed the presence ofalpha-polymorph material in an amount of 100% and comprised submicronsize particles. ‘-’ means not determined.

TABLE 5 Oil exudation (%) of the emulsions of examples 2 to 4 asfunction of the storage time at 15° C. Storage time Example 2 Example 3Example 4 1 day 5 0 0 4 days 18 0 0 5 days 40 0 0 1 week 45 0 0 2 weeks52 0.5 0 3 weeks 52 0.5 0 4 weeks 52 1 0 6 weeks 52 1.5 0 8 weeks 55 2 010 weeks 55 2 0 12 weeks 55 2 0 14 weeks 55 2 0.5 16 weeks 55 2 0.5

Examples 2-4 show that the addition of oil to the structuring agentprior to micronisation leads to a reduction in oil exudation of theemulsion prepared using the micronised structuring agent. The micronisedmixtures have a different appearance depending on the amount of oiladded.

Example 5

Micronised fat was prepared according to example 1, fat micronisationusing instead as fat rapeseed oil hardened to a slip melting point of68° C.

A dispersion of solid matter in a fat phase was prepared by firstpreparing a mixture of 4.6 parts (all parts are weight parts) micronisedfat in 4.6 parts sunflower oil and stirring the mixture for 3 minutes atabout 18° C. under vacuum. The obtained mixture was added to 49 partssunflower oil and mixed under vacuum at about 18° C. for 1 minute.

To this mixture was added 41.2 parts flour and 0.6 parts parsley flakes(dried) and the resulting mixture was stirred under vacuum at about 18°C. for 1 minute, 30 seconds. The resulting dispersion was stable formore than one month at room temperature without substantial oilexudation.

Example 6

A dispersion was prepared with the following composition (wt. % on finalproduct):

Flour 49% Dried herb pieces 1% Sunflower oil 45% Micronised fat powder(see example 5) 5%

The product was prepared by mixing all ingredients at room temperatureusing an ultraturrax mixing equipment. The product showed no oilexudation for one month.

Example 7

A dispersion was prepared similar to that of example 6, however using47.5 wt. % sunflower oil and 2.5 wt. % micronised fat prepared inexample 1. The processing was the same. When stored at 5° C. for onemonth, the product showed minimal oil exudation.

Examples 8 to 10

Example 1 was repeated, however instead of Rp70, SF69 (sunflower oilhardened to a slip melting point of 69° C.) was micronised and used ashardstock in the preparation of the emulsion.

To investigate how Ta (Equilibrium autoclave tmperature) influences themorphology of the powders after micronisation, three differentexperiments were performed at Ta=Tm−10° C. (Example 8), Ta=Tm−5° C.(Example 9) and Ta=Tm (Example 10) respectively, with P=180 bar, inwhich Tm is the melting point of the hardstock, for Rp69 in theseexample 69° C.

Xray diffraction showed that all micronised powders are in the apolymorph. SEM analysis shows no real differences in morphology withinthe chosen range of temperatures, although for Tm−10° C. (59° C.) andTm−5° C. (64° C.) the morphology seems to be a little more brittle thanfor Tm (69° C.).

Model Emulsions

Model emulsions were prepared using standard conditions and stored at15° C. and 25° C. In table 6, a summary of the measured oil exudation(O.E.) and Bostwick values (BW) as function of storage time is given.

TABLE 6 Results of Examples 8-10, Oil exudation (O.E. [%]) and Bostwickvalues (BW [cm]) as function of storage time and temperature Tm PBostwick value [cm] Example [° C.] [MPa] Start 2 wks 5 wks 9 wks 8 59 1810 10 10 9 9 64 18 12 11 11 10 10 69 18 10 9 10 10 O.E. at 15° C. O.E.at 25° C. 2 wks 5 wks 9 wks 2 wks 5 wks 9 wks 8 0 0 0 0.8 1.1 1.5 9 0 00 0 1.1 1.5 10 0 0 0 1.5 3.8 5.3

Results show that at Tm of 59° C. and 64° C., good O.E. and BW valuesafter 9 weeks were achieved. At Tm=69° C. the oil exudation at 25° C. isless favourable.

Enlarged SEM photographs (5000× magnification) of the micronised powdersof examples 8, 9 and 10 are shown in FIGS. 8, 9 and 10 respectively.

1. Process for the preparation of an edible dispersion comprising oiland structuring agent and one or more of an aqueous phase and/or a solidphase, in which the dispersion is formed by mixing oil, solidstructuring agent particles having a microporous structure of submicronsize particles and the aqueous phase and/or the solid phase, wherein thesolid structuring agent particles were made using a micronisationprocess by preparing a homogeneous mixture of structuring agent andliquefied gas or supercritical gas at a pressure of 5-40 MPa andexpanding the mixture through an orifice, under such conditions that aspray jet was applied in which the structuring agent was solidified andmicronised, wherein the homogeneous mixture was formed from a meltconsisting of edible fat which was mixed with liquefied gas orsupercritical gas.
 2. Process according to claim 1, wherein the solidstructuring agent particles are at least 50% alpha-polymorph.
 3. Processaccording to claim 1, wherein the structuring agent is edible fat. 4.Process according to claim 1, wherein the edible dispersion is a waterand oil containing emulsion, optionally including a solid phase. 5.Process according to claim 3, wherein the solid structuring agentparticles have an average diameter D_(3,2) of 60 μm or lower.
 6. Processaccording to claim 1, wherein the solid structuring agent particles havean average particle size D_(3,2) of 30 μm or lower.
 7. Process for thepreparation of an edible dispersion comprising oil and structuring agentand one or more of an aqueous phase and/or a solid phase, comprisingpreparing solid structuring agent particles using a micronisationprocess by preparing a homogeneous mixture of structuring agent andliquefied gas or supercritical gas at a pressure of 5-40 MPa andexpanding the mixture through an orifice, under such conditions that aspray jet is applied in which the structuring agent is solidified andmicronized, said structuring agent having a microporous structure ofsubmicron size particles, and forming the dispersion by mixing oil, thesolid structuring agent particles and the aqueous phase and/or the solidphase, and wherein the homogeneous mixture is formed from a meltconsisting of edible fat which is mixed with liquefied gas orsupercritical gas.
 8. (canceled)
 9. Process according to claim 1,wherein the homogenised mixture comprises oil.
 10. Process according toclaim 9, wherein the homogenised mixture comprises 10-90 wt. % based onthe weight of the sum of oil and structuring agent.
 11. Processaccording to claim 9, wherein the temperature of the mixture ofstructuring agent and liquified gas or supercritical gas is such thatthe mixture forms a homogeneous mixture.
 12. Process according to claim11, wherein the temperature of the mixture of structuring agent andliquified gas or supercritical gas is below the slip melting point ofthe structuring agent at atmospheric pressure and above the temperatureat which phase separation of the mixture occurs.
 13. Process accordingto claim 1, wherein a gas jet is applied in addition to the spray jet.14. Process according to claim 13, wherein the gas jet is positionedsuch that re-circulation of material expanded through the orifice isreduced or avoided.
 15. Process according to the claim 13, wherein thegas from the gas jet flows essentially tangentially to the flowdirection of the spray jet.
 16. Process according to claim 1, whereinthe spray jet is sprayed into a collection chamber, and a flow of gashaving a temperature lower than the slip melting point of thestructuring agent is fed into the collection chamber.
 17. (canceled) 18.Process according to claim 1, wherein the edible dispersion comprisingoil is a water and oil containing emulsion, and includes a solid phase.19. Process according to claim 1, wherein the edible dispersion is adispersion of 30-75 wt. % solid matter in oil.
 20. Process according toclaim 19, wherein the solid matter comprises dry particulate matter. 21.Process according to claim 20, wherein the dry particulate mattercomprises one or more of flour, starch, salt, dried herbs, spices andmixtures thereof.
 22. The process according to claim 1 wherein thehomogeneous mixture used to make the solid structuring agent comprisesstructuring agent and supercritical gas.
 23. The process according toclaim 22 wherein the supercritical gas is carbon dioxide.
 24. Theprocess according to claim 7 wherein the homogeneous mixture used tomake the solid structuring agent comprises structuring agent andsupercritical gas.
 25. The process according to claim 24 wherein thesupercritical gas is carbon dioxide.
 26. The process according to claim7 wherein the gas comprises carbon dioxide and the pressure is withinthe range of 15-40 MPa.
 27. The process according to claim 1 wherein inthe course of preparation of the dispersion the microporous structure isbroken into submicron particles.
 28. The process according to claim 7wherein in the course of preparation of the dispersion the microporousstructure is broken into the submicron particles.
 29. The processaccording to claim 1 wherein the wall thickness in the microporousstructure is submicron.
 30. The process according to claim 7 wherein thewall thickness in the microporous structure is submicron.
 31. Theprocess according to claim 22 wherein the gas comprises carbon dioxideand the pressure is within the range of 15-40 MPa.
 32. The processaccording to claim 1 wherein the edible dispersion is a spread, is oilcontinuous, and comprises an aqueous phase.
 33. The process according toclaim 7 wherein the edible dispersion is a spread, is oil continuous,and comprises an aqueous phase.